This application claims the benefit of the Korean Application No. P2002-0042521 filed on Jul. 19, 2002, which is hereby incorporated by reference.
1. Field of the Invention
The present invention relates to a thin film fabrication, and more particularly, to an apparatus and method for fabricating a carbon thin film. Although the present invention is suitable for a wide scope of applications, it is particularly suitable for forming a high density thin film and improving a deposition rate.
2. Discussion of the Related Art
Generally, when forming a carbon thin film, either a chemical vapor deposition (CVD) method using chemical reactions, or a sputtering method using physical collisions is used.
Being more advantageous in its uniformity in composition and thickness and its step coverage, the CVD method is more popular in fabrication processes of highly integrated semiconductor devices. A chemical source, a delivery system sending the chemical source to a reactor, a mass flow meter controlling the amount of the chemical source sent to the reactor, and a process chamber developing the chemical source into a thin film, such as a semiconductor thin film, through a chemical reaction are required for depositing thin film using the CVD method.
A gaseous chemical source is most generally used in the CVD method. However, when using a chemical source containing an element excessively high in atomic weight, it becomes difficult to form a gaseous chemical source. Therefore, a chemical source gas produced by vaporizing or sublimating a liquid or solid source through a vaporizer is used to deposit a thin film.
In general, the related art apparatus for sputtering includes a vacuum chamber having a substrate mounted therein to deposit a carbon thin film, an argon gas supplying unit supplying argon gas into the vacuum chamber, a target formed of graphite and spaced apart and facing into the substrate, and a power supply supplying power to the target.
In the above-described apparatus for sputtering, the vacuum chamber is filled with argon gas and a high voltage of DC or radio frequency (RF) voltage is applied to the target, so as to ionize the argon gas. The ionized argon gas collides with the target, thereby discharging carbon ions having momentum and accelerating energy. The carbon ions react on the surface of the substrate, thereby forming a thin film.
However, when using the above-described apparatus for depositing a thin film, a variety of gas supplied into the vacuum chamber is turned into active ions that are low in energy, so as to form a carbon thin film. Therefore, the adhesion of the thin film to the substrate becomes weak. This results in that the thin film may easily be detached from the substrate. In this case, the hardness of the carbon thin film tends to be lower than that of a CVD method.
In addition, when using the apparatus for sputtering, the sputtering of a target varies with the amount of introduced argon gas. However, the surface roughness, density, and interfacial characteristic vary with the sputtering of the target. In order to resolve this problem, supplementary equipment for producing an ion beam by using plasma may be used. However, even with this supplement, a high quality thin film is not formed.
Accordingly, the present invention is directed to an apparatus and method for fabricating a carbon thin film that substantially obviates one or more of problems due to limitations and disadvantages of the related art.
Another object of the present invention is to provide an apparatus and method for fabricating a carbon thin film, which has a low surface energy and enhanced hardness, surface roughness, and interfacial characteristic.
Additional features and advantages of the invention will be set forth in the description which follows and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, an apparatus for fabricating a carbon thin film includes a vacuum chamber having a substrate mounted therein, a sputter target inside the vacuum chamber facing into the substrate, a cesium supplying unit inside the vacuum chamber in a shape of a shield to a circumference of the target and supplying cesium vapor onto a surface of the sputter target through a plurality of openings, and a heating wire surrounding the cesium supplying unit and maintaining the cesium supplying unit at a constant pressure.
In another aspect of the present invention, an apparatus for fabricating a carbon thin film includes a vacuum chamber having a substrate mounted therein, a sputter target inside the vacuum chamber facing into the substrate, and a cesium supplying unit supplying cesium vapor (Cs) onto a surface of the sputter target from a central portion of the sputter target.
Herein, the cesium supplying unit includes a cesium storage unit storing cesium, a heating wire surrounding the cesium storage unit so as to heat or maintain the cesium storage unit at a constant temperature, and a cesium introduction tube supplying the cesium stored in the cesium storage unit to the surface of the target.
In a further aspect of the present invention, a method for fabricating a carbon thin film on a substrate includes maintaining a chamber at a constant vacuum pressure, vaporizing a cesium slurry formed of a mixture of liquid cesium and cesium-modernite, and concurrently introducing the vaporized cesium onto a sputter target and argon gas into the vacuum chamber in sputtering carbon ions from the sputter target, and forming the carbon thin film on the substrate from the sputtered carbon ions.
More specifically, the apparatus of the present invention vaporizes the cesium slurry formed of liquid cesium and cesium-modernite and supplies the vaporized cesium slurry to the target, and at the same time, introduces argon gas into the chamber so as to form a high quality diamond-like-carbon (DLC) thin film onto a hard disk.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.